Process of preparing oxy compounds of tantalum



Patented Sept. 9, 1924..

UNITED. STATES PATENT OFFICE.

HUGE SPENCER COOPER, F CLEVELAND, OHIO, ASSIGNOR T0 KEMET LABORATORIES COMPANY, INC., A CORPORATION OF'NEW YORK.

rzeocsss or rmemne oxx co'm'rouuns or" rennet.

' lio Drawing.

To all whom it may concern:

Be it known that 1, HUGE S. Coornn, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Processes of Preparing Ox Compounds of Tantalum, of

which the fo owing is' a specification.

This invention is a process for the prepa- 0 ration of high grade tantalum oxid from materials in which the tantalum :is associated with iron. Such materials are fairly cheap and abundant and are therefore pre ferred, as my invention provides for the removal of the iron, permitting the ultimate production of a white or nearly, white oxid. The invention includes the conversion- 0 the tantalum into chloridwhich is then 'hy-,

drolized into tantalic acid, the latter bein ignited to oxid if desired. The ferric rid initially formed, but this iron is removed with substantial completeness durdescribed, and as claimed.

My preferred startin material is ferrotantalum containing, orexample, about 80% Ta, as this is substantially free from 0 certain impurities normally associated with tantalum 1n nature. Tantalite and similar oxid'ores may, however, be employed.

The raw material is first treated with chlorin at a temperature above 450 Gland, preferably between 500 (land 650 C. If 0 about 5% 1101 or 5% H, O A prolonged tantalite or a similar oxid ore is used as raw material, this is pulverized and, mixed with carbonbeforethe chlorination to assist in manner as' to prevent their subsequent removal. Accordingly, Ifind it necessary tov effect the initial stages of hydratlon and hydrolysisin the presence 'of a deficiency of water and under conditions permitting the read dissipation of heat. When hydration andv ydrolysis have .passed acertam stage,

ing the process, all asmore fully hereinafter best results, this bo prepared chlorids to hydrolyze the Application fled m. 8,,1'922. Serial 1T0. seem.

' an excess of water may be addedto thematerial without undue formation of basic iron com ounds.

e preliminary treatment of'the mixed chloride may be conveniently accom lished b simply exposing the mixed chlori in a t in layer'to the action of air. Water va or f stated, the water should preferably be coldand the chlorids added slowly, as these precautions, in additlon to the open air' treatment, favor thefo'rmation of a product havchlorid formed from the iron in the start-m i111} material will contaminate the tantalumc o m a iron content.- Treatment with cold water hydrolyzes perhaps of the entire tantalum content of the mixed chloride and a further portion is caused to hydrolyze by boilin the mixture. For the g should be deferred untll-the'bu'lk of the tantalum chlorid is hydrolyzed, and the water should be fied before the boiling. A'suitab roporacidition of water to mixed chlorids during the boilin with-constant agitation is preferred, the so ution being conceptrat'ed teens-third its original bulk, or, if sulfuric acid was used, to a fluid paste. The concentrated solution containm the tantalum in suspension then we diluted, allowed to settle, decanted, washed thoroughly by 'decantation with cold and then hot, water, and

finally filtered and .washed until all solublef compounds are removed. Sodium chlorid has been found to b equivalent to acids-as an iron-hydrol sis-inhibitingagent under certain con 'tions. After 'themixed chlorids have been stirredinto cold water, as desc'ribed,'sodium chlorid maybe added until' the water has a 20% Na'Gl content,.gand the mixture then boiled decanted and washed without addition of acid. Ur, the mixed chloride maybe added to a cold 20% NaOl solution which is boiled without addition of acid after the bulk oi the tantalum oaid is hydrolyzed.

- The washed product obtained b an or the modifications described is drie an ignited to tantalum pentoxid, This ma contain columbium, ori ally associat with -.the tantalum, but i the process has been .the iron is rendered completely insoluble and cannot be removed inany feasible manner.

The steps w ich ll believe to be preferable when a product having a minimum content. of iron is to be repared. The process may be somewhat simplified for more rapid operation, giving a product which is less are but good enough for many uses. uch omissions and modifications, within the scope ot-the appended claims, are within my invention.

ll claim:

1; Process of preparing oxy-compounds of tantalum from material containing tantalum and iron, which comprises formingv a mixture of the chloride ofitantalum and iron, and then h drolyzing the'tantalum chlorid while inhi itating hydrolysis of the iron chlorid.

2. Process according to claim 1' in which the latter stages of the hydrolysis of the tantalum chlorid is efiected with boiling process as described includes all the nuances water in the presence of a hydrolysis-inhibiting agent' 3. Process according to claim 1 int which the mixed chlorids are prepared in anhydrous form and are subjected to prolonged exposure to air before actively hydrolyzing.

l. Process of preparing a mixture of tantalum and iron chloride which comprises treating a material containing tantalum and iron with 'chlorin at a temperature above 450 C.

5. Process according to claim 4 in which the tantalum-iron material is ferro-tantalum.

61.. Process of preparing oxy-compounds of tantalum from an anhydrous mixture of tantalum and iron chlorids, which comprises subjecting the mixedchlorids to the action of water-vapor and then more actively hydrolyzing the tantalum chlorid.

7. Process accordingto claim ti, in which the water-Va or used in the initial treat ment is high y diluted.

.8. Process according to claimt in which "the active hydrolysis comprises a. treatment.

with cold water.

9. Process accordingto claim 6 in which the active hydrolysis comprises a treatment with cold water followed by a treatment with hot water. i

Ell)

10. Process according to claim 9 in which the hot water treatment is carried out in the presence of a hydrolysis-inhibiting agent.

11. Process according to claim 10 in which the hydrolysis-inhibiting agent is a vchloriol.

12. Process according to claim 10in which the hydrolysis-inhibiting agent is a strong solution of sodium chlorid.

llntestimonyrwhereof, ll aflix my signature.

' HUGH SPENCER CUUPER. 

